This invention relates to fixtures very useful in the finishing of work pieces particularly in deburring and /or chamfering the edges thereof.
When a work piece such as a rectangular cross-section piece of wood, plastic or metal is finished by machining a face(s) on a milling machine or surface grinding machine, the resulting corners are very sharp and require deburring by the craftsman or machinist. Bar stock and plate or panel material processed by a mill can also exhibit sharp edges which must be smoothed on the finished product.
Current methods utilized include use of a hand file. This is time consuming and does not always yield a precise edge across a corner. Use of a belt or disk sander, hand held or floor or bench mounted, is less time consuming but, again may not produce accurate results due to the use of the human hand. There is also available bench or table top deburr/chamfer/bevel machines and hand held powered tools with right angle guides especially designed for deburr/chamfer/bevel use. However these powered tools are special purpose, relatively expensive machines.
Accordingly, the present invention provides an inexpensive fixture that permits accurate deburring, chamferring and beveling using an existing tool, normally found in a shop, such as a drill press, router or drum sander.
An object of this invention is to provide a new and improved fixture for use with a rotary cutting or stock removal tool commonly found in a metal working, wood shop or plastic finishing shop.
Another object of this invention is to provide a new, improved and inexpensive fixture, which may be employed with standard or common shop tools for the purpose of deburring, chanferring and/or beveling a work piece.
A further object of this invention is to a new and improved fixture of the type described which is compact in design and readily adaptable to existing tools.
Briefly stated, the invention, in one form there as utilized with a drill press or other tool having a cutting bit rotatable about a vertical axis comprises a member having opposite sides with a recess defined in a first of the sides by two surfaces at right angles to each other to defining guide surfaces for a work piece. The opposite side resides in a plane essentially perpendicular to a plane bisecting the angle between the surfaces. A semi-cylindrical recess is defined into the member in the opposite side, intermediate the ends thereof, about an axis which is essentially perpendicular to a plane bisecting the angle between the surfaces. The passage extends through a portion of the guide surfaces and defines an opening in the guide surfaces whereby a rectangular cross section work piece contacting the guide surfaces will extend through the opening into the passage. A guard member having a cylindrical upper portion and a semi-cylindrical depending lower portion is affixed to the member essentially coaxial with the passage thereby, enclosing the semi-cylindrical recess and defining with the member a cylindrical recess. The fixture may be clamped to the worktable of a drill press and a rotary cutting tool inserted into the cylindrical recess to act on a work piece extending through the opening.
A fixture embodying the invention may be modified with respect to the foregoing description to accept a cutting tool having a cutting bit rotatable about a horizontal axis. In such modification the fixture is mounted to a vertical support extending from a base support member. The fixture is mounted to the vertical support with the angle of the guide surfaces bisected by a vertical plane. The cutting tool, usually a router designed to be hand held, is mounted to the opposite side of the vertical support. The cutting bit extends through an aperture into the semi-cylindrical recess in the fixture and positioned to act on the corner of a work piece extending through the opening. A hollow member, supported on the base support member is positioned below the semi-cylindrical recess in close proximity to the fixture to catch cut chips, saw dust, etc. and also act as a safety guard about the cutting bit.
In general, a fixture embodying the invention is removeably mounted with respect to the bit of a rotary cutting tool in operative relation thereto to achieve the desired deburring, chamfering or beveling.
The invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. The invention, however, together with further objects and advantages thereof, may best be appreciated by reference to the following detailed descriptions taken in conjunction with the drawings.